Answer : Not always. However, it is becoming more and more common for interior designers to earn a degree in the field. This is because the field of interior design is becoming increasingly complex, with new technologies and materials being introduced all the time.
That said, there are some excellent interior designers who have never earned a degree. So it ultimately depends on your skills, experience, and portfolio. If you're talented and have a strong portfolio, you may be able to find work without a degree. But if you're just starting out, then I would recommend earning a degree in interior design from an accredited school.